libstdc++
malloc_allocator.h
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1 // Allocator that wraps "C" malloc -*- C++ -*-
2 
3 // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
4 // Free Software Foundation, Inc.
5 //
6 // This file is part of the GNU ISO C++ Library. This library is free
7 // software; you can redistribute it and/or modify it under the
8 // terms of the GNU General Public License as published by the
9 // Free Software Foundation; either version 3, or (at your option)
10 // any later version.
11 
12 // This library is distributed in the hope that it will be useful,
13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 // GNU General Public License for more details.
16 
17 // Under Section 7 of GPL version 3, you are granted additional
18 // permissions described in the GCC Runtime Library Exception, version
19 // 3.1, as published by the Free Software Foundation.
20 
21 // You should have received a copy of the GNU General Public License and
22 // a copy of the GCC Runtime Library Exception along with this program;
23 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
24 // <http://www.gnu.org/licenses/>.
25 
26 /** @file ext/malloc_allocator.h
27  * This file is a GNU extension to the Standard C++ Library.
28  */
29 
30 #ifndef _MALLOC_ALLOCATOR_H
31 #define _MALLOC_ALLOCATOR_H 1
32 
33 #include <cstdlib>
34 #include <new>
35 #include <bits/functexcept.h>
36 #include <bits/move.h>
37 
38 _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
39 
40  using std::size_t;
41  using std::ptrdiff_t;
42 
43  /**
44  * @brief An allocator that uses malloc.
45  * @ingroup allocators
46  *
47  * This is precisely the allocator defined in the C++ Standard.
48  * - all allocation calls malloc
49  * - all deallocation calls free
50  */
51  template<typename _Tp>
53  {
54  public:
55  typedef size_t size_type;
56  typedef ptrdiff_t difference_type;
57  typedef _Tp* pointer;
58  typedef const _Tp* const_pointer;
59  typedef _Tp& reference;
60  typedef const _Tp& const_reference;
61  typedef _Tp value_type;
62 
63  template<typename _Tp1>
64  struct rebind
65  { typedef malloc_allocator<_Tp1> other; };
66 
67  malloc_allocator() throw() { }
68 
69  malloc_allocator(const malloc_allocator&) throw() { }
70 
71  template<typename _Tp1>
72  malloc_allocator(const malloc_allocator<_Tp1>&) throw() { }
73 
74  ~malloc_allocator() throw() { }
75 
76  pointer
77  address(reference __x) const { return &__x; }
78 
79  const_pointer
80  address(const_reference __x) const { return &__x; }
81 
82  // NB: __n is permitted to be 0. The C++ standard says nothing
83  // about what the return value is when __n == 0.
84  pointer
85  allocate(size_type __n, const void* = 0)
86  {
87  if (__builtin_expect(__n > this->max_size(), false))
88  std::__throw_bad_alloc();
89 
90  pointer __ret = static_cast<_Tp*>(std::malloc(__n * sizeof(_Tp)));
91  if (!__ret)
92  std::__throw_bad_alloc();
93  return __ret;
94  }
95 
96  // __p is not permitted to be a null pointer.
97  void
98  deallocate(pointer __p, size_type)
99  { std::free(static_cast<void*>(__p)); }
100 
101  size_type
102  max_size() const throw()
103  { return size_t(-1) / sizeof(_Tp); }
104 
105  // _GLIBCXX_RESOLVE_LIB_DEFECTS
106  // 402. wrong new expression in [some_] allocator::construct
107  void
108  construct(pointer __p, const _Tp& __val)
109  { ::new((void *)__p) value_type(__val); }
110 
111 #ifdef __GXX_EXPERIMENTAL_CXX0X__
112  template<typename... _Args>
113  void
114  construct(pointer __p, _Args&&... __args)
115  { ::new((void *)__p) _Tp(std::forward<_Args>(__args)...); }
116 #endif
117 
118  void
119  destroy(pointer __p) { __p->~_Tp(); }
120  };
121 
122  template<typename _Tp>
123  inline bool
124  operator==(const malloc_allocator<_Tp>&, const malloc_allocator<_Tp>&)
125  { return true; }
126 
127  template<typename _Tp>
128  inline bool
129  operator!=(const malloc_allocator<_Tp>&, const malloc_allocator<_Tp>&)
130  { return false; }
131 
132 _GLIBCXX_END_NAMESPACE
133 
134 #endif
ISO C++ entities toplevel namespace is std.
GNU extensions for public use.
An allocator that uses malloc.This is precisely the allocator defined in the C++ Standard.